Speaker
Description
In scenarios with very small dark matter (DM) couplings and small mass splittings between the DM and other dark-sector particles, so-called "coscattering" or "conversion-driven freeze-out" can be the dominant mechanism for DM production. They hence also tend to feature long-lived dark-sector particles with longer lifetimes than in the well-known coannihilation case. In this talk, we present the inclusion of this mechanism in micrOMEGAs together with a case study of the phenomenological implications in the singlet-triplet model. We observe that coscattering is needed to describe the thermal behaviour of the DM for very small couplings and it opens up a new region in the parameter space of the model. Long-lived particle constraints from the LHC, evaluated with SModelS, are found to exclude a large part of this region, up to DM masses of about 500 GeV for the smallest lifetimes considered.
